Molecular sieve CIT-6

ABSTRACT

The present invention relates to new crystalline, molecular sieve CIT-6 that has the topology of zeolite beta. CIT-6 can be in an all-silica form, in a form wherein zinc is in the crystal framework, or a form containing silicon oxide and non-silicon oxides. In a preferred embodiment, CIT-6 has a crystal size of less than one micron and a water adsorption capacity of less than 0.05 g/g.

This application is a division of application Ser. No. 09/288,247, Apr.8, 1999, now U.S. Pat. No. 6,117,411, which is a continuation-in-part ofapplication Ser. No. 09/106,598, filed Jun. 29, 1998, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to new crystalline molecular sieve CIT-6,a method for preparing CIT-6 using a tetraethylammonium cationtemplating agent, a method of using CIT-6 as a precursor for makingother crystalline molecular sieves, and processes employing CIT-6 as acatalyst.

2. State of the Art

Because of their unique sieving characteristics, as well as theircatalytic properties, crystalline molecular sieves are especially usefulin applications such as hydrocarbon conversion, gas drying andseparation. Although many different crystalline molecular sieves havebeen disclosed, there is a continuing need for new molecular sieves withdesirable properties for gas separation and drying, hydrocarbon andchemical conversions, and other applications. New molecular sieves maycontain novel internal pore architectures, providing enhancedselectivities in these processes.

SUMMARY OF THE INVENTION

The present invention is directed to a crystalline molecular sieve withunique properties, referred to herein as “molecular sieve CIT-6” orsimply “CIT-6”. When the CIT-6 contains a metal (or non-silicon) oxide,such as aluminum oxide, boron oxide, titanium oxide or iron oxide, it isreferred to as “catalytically active” CIT-6.

The CIT-6 can be made in two forms. The first contains silicon oxide,zinc oxide and optional metal (or non-silicon) oxides (such as aluminumoxide), wherein the zinc is in the crystal framework of the CIT-6. Thisform of CIT-6 is referred to herein as “Zn-CIT-6”.

Another form of CIT-6 is where the molecular sieve is composed only ofsilicon oxide. This form of CIT-6 is referred to herein as “all-SiCIT-6”.

Zn-CIT-6 and all-Si CIT-6 each have the topology of zeolite beta.

In accordance with this invention, there is provided a molecular sievecomprising an oxide of silicon and an oxide of zinc and having theframework topology of zeolite beta, wherein the molecular sieve containszinc in its crystal framework.

The present invention further provides such a molecular sieve having thetopology of zeolite beta, and having a composition, as synthesized andin the anhydrous state, in terms of mole ratios as follows:

SiO₂/ZnO 10-100

M/SiO₂ 0.01-0.1

Q/SiO₂ 0.07-0.14

wherein M is lithium or a mixture of lithium and another alkali metal,and Q comprises a tetraethylammonium cation, wherein the molecular sievecontains zinc in its crystal framework.

Also in accordance with this invention there is provided a molecularsieve comprising silicon oxide, zinc oxide, and an oxide selected fromaluminum oxide, boron oxide, gallium oxide, iron oxide, titanium oxide,vanadium oxide, zirconium oxide, tin-oxide or mixtures thereof andhaving the framework topology of zeolite beta, wherein the molecularsieve contains zinc in its crystal framework.

The present invention also provides such a molecular sieve having thetopology of zeolite beta, and having a composition, as synthesized andin the anhydrous state, in terms of mole ratios as follows:

SiO₂/ZnO 10-100

SiO₂/W 30-250

M/SiO₂ 0.01-0.1

Q/SiO₂ 0.07-0.14

wherein W is an oxide of aluminum, boron, gallium, vanadium, iron,titanium or mixtures thereof M is lithium or a mixture of lithium andanother alkali metal, and Q comprises a tetraethylammonium cation,wherein the molecular sieve contains zinc in its crystal framework.

Also provided in accordance with the present invention is a method ofpreparing a crystalline material comprising an oxide of silicon and anoxide of zinc and having the framework topology of zeolite beta, whereinthe molecular sieve contains zinc in its crystal framework, said methodcomprising contacting in admixture under crystallization conditionssources of said oxides, a source of lithium or a mixture of lithium andanother alkali metal and a templating agent comprising atetraethylammonium cation.

The present invention also provides a method of preparing a crystallinematerial comprising an oxide of silicon, an oxide of zinc and an oxideselected from aluminum oxide, boron oxide, gallium oxide, vanadiumoxide, iron oxide, titanium oxide or mixtures thereof and having theframework topology of zeolite beta, wherein the molecular sieve containszinc in its crystal framework, said method comprising contacting inadmixture under crystallization conditions sources of said oxides, asource of lithium or a mixture of lithium and another alkali metal and atemplating agent comprising a tetraethylammonium cation.

Further provided by the present invention is a method of removing atetraethylammonium organic template from the pores of a molecular sieve,said method comprising contacting the molecular sieve with acetic acid,or a mixture of acetic acid and pyridine at elevated temperature for atime sufficient to remove essentially all of the tetraethylammoniumorganic template from the molecular sieve. In a preferred embodiment,the molecular sieve has the topology of zeolite beta.

The present invention further provides a method of removing an organictemplate from the pores of a molecular sieve and at the same timeremoving zinc atoms from the framework of the molecular sieve, whereinthe molecular sieve comprises an oxide of silicon, an oxide of zinc and,optionally an oxide selected from aluminum oxide, boron oxide, galliumoxide, vanadium oxide, iron oxide, titanium oxide or mixtures thereof,and has the framework topology of zeolite beta, said method comprisingcontacting the molecular sieve with acetic acid or a mixture of aceticacid and pyridine at elevated temperature for a time sufficient toremove essentially all of the organic template and zinc from themolecular sieve. The present invention also provides the product of thismethod.

Also provided by the present invention is a method of making acrystalline material comprising (1) contacting in admixture undercrystallization conditions a source of silicon oxide, a source of zincoxide, a source of lithium or a mixture of lithium and another alkalimetal and a templating agent comprising a tetraethylammonium cationuntil a crystalline material comprised of oxides of silicon and zinc andhaving the topology of zeolite beta is formed, (2) contacting thecrystals with acetic acid or a mixture of acetic acid and pyridine at anelevated temperature of about 60° C. or less for a time sufficient toremove essentially all of the organic template and zinc from thecrystals, and (3) contacting the crystals with a solution containing asource of aluminum, boron, gallium, iron, vanadium, titanium, zirconium,tin or mixtures thereof. The present invention also provides the productof this method.

This invention also provides a crystalline molecular sieve having thetopology of zeolite beta, a crystal size of less than one micron and awater adsorption capacity of less than 0.05 g/g of molecular sieve.

Further provided by the present invention is a crystalline silicatemolecular sieve having the topology of zeolite beta, a crystal size ofless than one micron and a water adsorption capacity of less than 0.05g/g of molecular sieve.

In addition, the present invention provides a method of preparing acrystalline material having the topology of zeolite beta comprisingimpregnating a silica-containing mesoporous material with an aqueoussolution comprising tetraethylammonium cation in an amount sufficient toform a crystalline product having the topology of zeolite beta, andwherein the water to mesoporous material molar ratio is from about 0.5to about 2, and subjecting the impregnated mesoporous material tocrystallizing conditions of heat and pressure for a time sufficient toform crystals of a material having the topology of zeolite beta.

The present invention additionally provides a process for convertinghydrocarbons comprising contacting a hydrocarbonaceous feed athydrocarbon converting conditions with a catalyst comprising acatalytically active molecular sieve comprising silicon oxide, zincoxide, and an oxide selected from aluminum oxide, boron oxide, galliumoxide, iron oxide, zirconium oxide, tin oxide or mixtures thereof andhaving the framework topology of zeolite beta, wherein the molecularsieve contains zinc in its crystal framework. The molecular sieve may bepredominantly in the hydrogen form, partially acidic or substantiallyfree of acidity, depending on the process.

Further provided by the present invention is a hydrocracking processcomprising contacting a hydrocarbon feedstock under hydrocrackingconditions with a catalyst comprising the catalytically active molecularsieve of this invention, preferably predominantly in the hydrogen form.

This invention also includes a dewaxing process comprising contacting ahydrocarbon feedstock under dewaxing conditions with a catalystcomprising the catalytically active molecular sieve of this invention,preferably predominantly in the hydrogen form.

The present invention also includes a process for improving theviscosity index of a dewaxed product of waxy hydrocarbon feedscomprising contacting the waxy hydrocarbon feed under isomerizationdewaxing conditions with a catalyst comprising the catalytically activemolecular sieve of this invention, preferably predominantly in thehydrogen form.

The present invention further includes a process for producing a C₂₀₊lube oil from a C₂₀₊ olefin feed comprising isomerizing said olefin feedunder isomerization conditions over a catalyst comprising at least oneGroup VIII metal and the catalytically active molecular sieve of thisinvention. The molecular sieve may be predominantly in the hydrogenform.

In accordance with this invention, there is also provided a process forcatalytically dewaxing a hydrocarbon oil feedstock boiling above about350° F. and containing straight chain and slightly branched chainhydrocarbons comprising contacting said hydrocarbon oil feedstock in thepresence of added hydrogen gas at a hydrogen pressure of about 15-3000psi with a catalyst comprising at least one Group VIII metal and thecatalytically active molecular sieve of this invention, preferablypredominantly in the hydrogen form. The catalyst may be a layeredcatalyst comprising a first layer comprising at least one Group VIIImetal and the catalytically active molecular sieve of this invention,and a second layer comprising an aluminosilicate zeolite which is moreshape selective than the catalytically active molecular sieve of saidfirst layer.

Also included in the present invention is a process for preparing alubricating oil which comprises hydrocracking in a hydrocracking zone ahydrocarbonaceous feedstock to obtain an effluent comprising ahydrocracked oil, and catalyticay dewaxing said effluent comprisinghydrocracked oil at a temperature of at least about 400° F. and at apressure of from about 15 psig to about 3000 psig in the presence ofadded hydrogen gas with a catalyst comprising at least one Group VIIImetal and the catalytically active molecular sieve of this invention.The molecular sieve may be predominantly in the hydrogen form.

Further included in this invention is a process for isomerizationdewaxing a raffinate comprising contacting said raffinate in thepresence of added hydrogen with a catalyst comprising at least one GroupVIII metal and the catalytically active molecular sieve of thisinvention. The raffinate maybe bright stock, and the molecular sieve maybe predominantly in the hydrogen form.

Also included in this invention is a process for increasing the octaneof a hydrocarbon feedstock to produce a product having an increasedaromatics content comprising contacting a hydrocarbonaceous feedstockwhich comprises normal and slightly branched hydrocarbons having aboiling range above about 40° C. and less than about 200° C., underaromatic conversion conditions with a catalyst comprising thecatalytically active molecular sieve of this invention madesubstantially free of acidity by neutralizing said molecular sieve witha basic metal. Also provided in this invention is such a process whereinthe molecular sieve contains a Group VIII metal component.

Also provided by the present invention is a catalytic cracking processcomprising contacting a hydrocarbon feedstock in a reaction zone undercatalytic cracking conditions in the absence of added hydrogen with acatalyst comprising the catalytically active molecular sieve of thisinvention, preferably predominantly in the hydrogen form. Also includedin this invention is such a catalytic cracking process wherein thecatalyst additionally comprises a large pore crystalline crackingcomponent.

Also provided by the present invention is a process for alkylating anaromatic hydrocarbon which comprises contacting under alkylationconditions at least a molar excess of an aromatic hydrocarbon with a C₂to C₂₀ olefin under at least partial liquid phase conditions and in thepresence of a catalyst comprising the catalytically active molecularsieve of this invention, preferably predominantly in the hydrogen form.The olefin may be a C₂ to C₄ olefin, and the aromatic hydrocarbon andolefin may be present in a molar ratio of about 4:1 to about 20:1,respectively. The aromatic hydrocarbon may be selected from the groupconsisting of benzene, toluene, ethylbenzene, xylene, or mixturesthereof Further provided in accordance with this invention is a processfor transalkylating an aromatic hydrocarbon which comprises contactingunder transalkylating conditions an aromatic hydrocarbon with apolyalkyl aromatic hydrocarbon under at least partial liquid phaseconditions and in the presence of a catalyst comprising thecatalytically active molecular sieve of this invention, preferablypredominantly in the hydrogen form. The aromatic hydrocarbon and thepolyalkyl aromatic hydrocarbon may be present in a molar ratio of fromabout 1:1 to about 25:1, respectively. The aromatic hydrocarbon may beselected from the group consisting of benzene, toluene, ethylbenzene,xylene, or mixtures thereof, and the polyalkyl aromatic hydrocarbon maybe a dialkylbenzene.

Further provided by this invention is a process to convert paraffins toaromatics which comprises contacting paraffins under conditions whichcause paraffins to convert to aromatics with a catalyst comprising thecatalytically active molecular sieve of this invention, said catalystcomprising gallium, zinc, or a compound of gallium or zinc.

In accordance with this invention there is also provided a process forisomerizing olefins comprising contacting said olefin under conditionswhich cause isomerization of the olefin with a catalyst comprising thecatalytically active molecular sieve of this invention.

Further provided in accordance with this invention is a process forisomerizing an isomerization feed comprising an aromatic Cs stream ofxylene isomers or mixtures of xylene isomers and ethylbenzene, wherein amore nearly equilibrium ratio of ortho-, meta- and para-xylenes isobtained, said process comprising contacting said feed underisomerization conditions with a catalyst comprising the catalyticallyactive molecular sieve of this invention.

The present invention further provides a process for oligomerizingolefins comprising contacting an olefin feed under oligomerizationconditions with a catalyst comprising the catalytically active molecularsieve of this invention.

This invention also provides a process for converting lower alcohols andother oxygenated hydrocarbons comprising contacting said lower alcoholor other oxygenated hydrocarbon with a catalyst comprising thecatalytically active molecular sieve of this invention under conditionsto produce liquid products.

Also provided by the present invention is an improved process for thereduction of oxides of nitrogen contained in a gas stream in thepresence of oxygen wherein said process comprises contacting the gasstream with a molecular sieve, the improvement comprising using as themolecular sieve, the molecular sieve of this invention. The molecularsieve may contain a metal or metal ions (such as cobalt, copper ormixtures thereof) capable of catalyzing the reduction of the oxides ofnitrogen, and may be conducted in the presence of a stoichiometricexcess of oxygen. In a preferred embodiment, the gas stream is theexhaust stream of an internal combustion engine.

Further provided by the present invention is a method of removing liquidorganic compounds from a mixture of liquid organic compounds and water,comprising contacting the mixture with an all-silica molecular sievehaving the framework topology of zeolite beta, a crystal size less thanone micron and a water adsorption capacity of less than 0.05 g/g ofmolecular sieve.

The present invention further provides a method of removing liquidorganic compounds from a mixture of liquid organic compounds and water,comprising contacting the mixture with a molecular sieve comprising anoxide of silicon, an oxide of zinc and, optionally, an oxide selectedfrom aluminum oxide, boron oxide, gallium oxide, iron oxide, vanadiumoxide, titanium oxide, zirconium oxide, tin oxide and mixtures thereof,and having the framework topology of zeolite beta, wherein the molecularsieve contains zinc in its crystal framework.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 show the results of water adsorption isotherms at 25° C.of the molecular sieves of this invention and beta zeolite.

DETAILED DESCRIPTION OF THE INVENTION

In preparing CIT-6 molecular sieves, a tetraethylammonium cation (“TEA”)is used as a crystallization template (also known as a structuredirecting agent, or SDA). The anion associated with the cation may beany anion which is not detrimental to the formation of the molecularsieve. Representative anions include halogen, e.g., fluoride, chloride,bromide and iodide, hydroxide, acetate, sulfate, tetrafluoroborate,carboxylate, and the like. Hydroxide is the most preferred anion.

In general, Zn-CIT-6 is prepared by contacting an active source ofsilicon oxide, an active source of zinc oxide, an active source oflithium or mixture of lithium and another alkali metal with the TEAtemplating agent.

Zn-CIT-6 is prepared from a reaction mixture having the followingcomposition:

bM:cTEA:aZnO:SiO2:dH2O

where M is lithium or a mixture of lithium and another alkali metal,b=0.05-0.1; c=0.55-0.7; a=0.03-0.05; d=3040. It is believed theconcentrations of Li⁺, Zn²⁺ and TEAOH are critical to the formation ofZn-CIT-6.

When it is desired to prepare Zn-CIT-6 containing zinc oxide incombination with another metal oxide, such as aluminum oxide, a reactionmixture having the following composition:

bM:cTEA:aZnO:SiO2:e:dH2O

where M is lithium or a mixture of lithium and another alkali metal, Wis an oxide of aluminum, boron, gallium, vanadium, iron, titanium ormixtures thereof; b, c, a and d are as defined above and e=0.005-0.1.

In practice, Zn-CIT-6 is prepared by a process comprising:

(a) preparing an aqueous solution containing sources of silicon oxide,zinc oxide, lithium or a mixture of lithium and another alkali metal,TEA having an anionic counterion which is not detrimental to theformation of Zn-CIT-6, and, optionally, an oxide selected from aluminumoxide, boron oxide, gallium oxide, vanadium oxide, iron oxide, titaniumoxide or mixtures thereof;

(b) maintaining the aqueous solution under conditions sufficient to formcrystals of Zn-CIT-6; and

(c) recovering the crystals of Zn-CIT-6.

The aqueous solution prepared in step (a) should be a clear solution. Insome cases, heating a reaction mixture that is a white, cloudy mixtureat room temperature will convert the mixture to a clear solution fromwhich Zn-CIT-6 will form.

It has been discovered that higher amounts of TEA and lower reactiontemperatures favor the formation of Zn-CIT-6.

Typical sources of silicon oxide include silicates, silica hydrogel,silicic acid, fumed silica, colloidal silica, tetra-alkylorthosilicates, and silica hydroxides. Typical sources of zinc oxideinclude water-soluble zinc salts, such as zinc acetate. Typical sourcesof aluminum oxide for the reaction mixture include aluminates, alumina,aluminum colloids, aluminum oxide coated on silica sol, and hydratedalumina gels such as Al(OH)₃. Sources of boron, gallium, vanadium, ironand titanium compounds analogous to those listed for silicon andaluminum, and are known in the art.

Lithium or a mixture of lithium and another alkali metal is added to thereaction mixture. A variety of sources can be used, such as alkali metalhydroxides and alkali metal carbonates, with lithium hydroxide beingparticularly preferred. The lithium cation may be part of theas-synthesized crystalline oxide material, in order to balance valenceelectron charges therein. Other alkali metals which can be used incombination with the lithium include sodium and potassium, with thehydroxides being preferred, provided that lithium is the predominantalkali metal in the combination.. The alkali metal (i.e., lithium ormixture of lithium and another alkali metal) may be employed in anamount of from about 0.05 to about 0.1 mole of alkali metal per mole ofsilica.

The reaction mixture is maintained at an elevated temperature until thecrystals of the Zn-CIT-6 molecular sieve are formed. The hydrothermalcrystallization is usually conducted under autogenous pressure, at about100° C. to less than about 150° C. It has been discovered that higherreaction temperatures, e.g., 150° C. and higher, favor the formation ofa molecular sieve having the topology of zeolite VPI-8 rather than thedesired molecular sieve with the topology of zeolite beta. Preferably,the reaction temperature should be about 135° C. to 150° C.

The crystallization period is typically greater than 1 day to less than7 days. The Zn-CIT-6 crystals should be recovered from the reactionmixture as soon as they form, since it has been discovered that undersome circumstances if they remain in the reaction mixture for too longafter formation, they can convert to a molecular sieve having thetopology of VPI-8.

During the hydrothermal crystallization step, the Zn-CIT-6 crystals-canbe allowed to nucleate spontaneously from the reaction mixture. The useof Zn-CIT-6 crystals as seed material can be advantageous in decreasingthe time necessary for complete crystallization to occur. In addition,seeding can lead to an increased purity of the product obtained bypromoting the nucleation and/or formation of Zn-CIT-6 over any undesiredphases. When used as seeds, Zn-CIT-6 crystals are added in an amountbetween 0.1 and 10% of the weight of silica used in the reactionmixture.

Once the molecular sieve crystals have formed, the solid product isseparated from the reaction mixture by standard mechanical separationtechniques such as filtration. The crystals are water-washed and thendried, e.g., at 90° C. to 150° C. for from 8 to 24 hours, to obtain theas-synthesized Zn CIT-6 molecular sieve crystals. The drying step can beperformed at atmospheric pressure or under vacuum.

Zn-CIT-6 has a composition, as synthesized and in the anhydrous state,in terms of mole ratios, shown in Table B below.

TABLE B As-Synthesized Zn-CIT-6 SiO₂/ZnO  10-100 M/SiO₂ 0.01-0.1  Q/SiO₂0.07-0.14

where M and Q are as defined above.

Zn-CIT-6 can also have a composition, as synthesized and in theanhydrous state, in terms of mole ratios, shown in Table C below.

TABLE C As-Synthesized Zn-CIT-6 SiO₂/ZnO  10-100 SiO₂/W  30-250 M/SiO₂0.01-0.1  Q/SiO₂ 0.07-0.14

where W, M and Q are as defined above.

Solid state ²⁹Si NMR analysis and acidity measurements have shown thatat least part of the zinc is in the framework of the Zn-CIT-6 crystals.Indeed, in one embodiment, the Zn-CIT-6 crystal framework contains onlysilicon, zinc and oxygen atoms, i.e., there are no other metals in thisform of Zn-CIT-6.

Once the Zn-CIT-6 crystals have been formed and recovered, the organictemplate should be removed. This is typically done by calcining thecrystals at high temperature until the organic template is removed.However, it has been discovered that calcination can be avoided byextracting the organic template from the molecular sieve. Thisextraction technique has advantages over calcination. For example, nocalcination equipment is needed. Also, the organic template is notdestroyed by the extraction, so it may be possible to recycle it,thereby reducing the cost of maling the molecular sieve.

The organic template can be removed by contacting the Zn-CIT-6 crystalswith acetic acid or a mixture of acetic acid and pyridine at atemperature of about 80° C. to about 135° C. for a period sufficient toremove essentially all of the organic template from the crystals(typically about two days). At the same time, the zinc is removed fromthe crystals, and they convert to all-Si CIT-6, i.e., an all-silicacrystal having the framework topology of zeolite beta. As shown by wateradsorption isotherms, all-Si CIT-6 is highly hydrophobic. ²⁹Si NMRanalysis further shows that the crystal lattice has virtually nodefects.

It has quite surprisingly been found that CIT-6 prepared as describedabove, i.e., the CIT-6 is prepared and then contacted with acetic acidor a mixture of acetic acid and pyridine at a temperature of about 80°C. to about 135° C. (referred to herein as “extraction”), is highlyhydrophobic. This is in marked contrast to CIT-6 or beta zeolite inwhich the organic template has been removed by calcination.

This phenomenon is illustrated in the FIG. 1. Five water adsorptionisotherms are shown for the following materials:

(a) All-Si-CIT-6 prepared by extraction at 135° C.

(b) Zn-CIT-6 prepared using calcination

(c) Silicoalumino-CIT-6 extracted at 60° C. followed by insertion ofaluminum

(d) Silicoalumino-CIT-6 prepared using aluminum oxide in the reactionmixture with the product extracted at 135° C.

(e) Calcined all-silica beta zeolite

The data indicate that the extracted aluminum-containing CIT-6 (sampled) is more hydrophobic than the sample prepared via aluminum insertion(sample c) and far more hydrophobic than the calcined zeolite beta(sample e). Calcined Zn-CIT-6 (sample b) likewise is far morehydrophobic than calcined zeolite beta, with extracted all-Si-CIT-6(sample a) exhibiting the highest degree of hydrophobicity.

Alternatively, the extraction or removal of the organic template fromZn-CIT-6 can be accomplished by contacting the Zn-CIT-6 crystal withacetic acid or a mixture of acetic acid and pyridine at an elevatedtemperature of about 60° C. or less for a period sufficient to removeessentially all of the organic template from the crystals.

It has also been found that this latter extraction technique alsoremoves some or all of the zinc atoms from the crystal framework.However, in this case the resultant molecular sieve contains internalsilanol groups and other metals (or non-silicon atoms), such asaluminum, boron, gallium, vanadium, iron, titanium, zirconium, tin ormixtures thereof can be inserted into the crystal framework, replacingthe zinc.

The metal can be inserted into the crystal framework by contacting themolecular sieve with a solution containing a source, such as a salt, ofthe desired metal. Although a wide variety of sources can be employed,chlorides and other halides, acetates, nitrates, and sulfates areparticularly preferred. The preferred metals (or non-silicon atoms) arealuminum, boron, gallium, iron, titanium, vanadium, zirconium, tin, zincand mixtures thereof. Representative techniques for inserting the metalare disclosed in a wide variety of patents including U.S. Pat. No.3,140,249, issued Jul. 7, 1964 to Plank et al.; U.S. Pat. No. 3,140,251,issued on Jul. 7, 1964 to Plank et al.; and U.S. Pat. No. 3,140,253,issued on Jul. 7, 1964 to Plank et al., each of which is incorporated byreference herein. By way of example, aluminum can be inserted into themolecular sieve in place of some or all of the zinc by extracting thezinc (at about 60° C.) as described above, and then contacting themolecular sieve with an aluminum nitrate solution in about a 1:2:50weight ratio of sieve:aluminum nitrate:water at about 80° C. for aboutone day.

As an alternative to making Zn-CIT-6, extracting the zinc and inserting,e.g., aluminum, an aluminosilicate can be made directly by synthesizingaluminozincosilicate CIT-6 as described above and in Example 27, andthen extracting the zinc at the higher extraction temperature (135° C.).This removes the zinc from the CIT-6 and leaves an aluminosilicatemolecular sieve with the topology of zeolite beta. ²⁷Al NMR analysis ofaluminosilicates made in this manner shows that the aluminum remains inthe crystal framework.

All-Si CIT-6 can be made by preparing Zn-CIT-6 as described above,followed by extraction of the zinc. It has surprisingly been found thatall-Si CIT-6 made by this method has a much lower water adsorptioncapacity than all-silica zeolite beta made by traditional methods. Theall-Si CIT-6 made by this method also has a crystal size of less thanabout one micron, whereas all-silica zeolite beta made by traditionalmethod has a crystal size of greater than one micron, e.g., on the orderof five microns. Furthermore, the all-Si CIT-6 made by this method hasessentially no defect (i.e., Si—OH instead of Si—O—Si) sites, whereasall-silica zeolite beta made by traditional methods does contain defectsites that adsorb water.

A series of silica-containing mesoporous materials denoted M41S havebeen reported. These materials have been further classified, e.g.,MCM-41 (hexagonal), MCM-48 (cubic) and others. These materials haveuniform pores of 1.5-10 nm diameters, and are made by using a variety ofsurfactants as structure-directing agents. Non-silicon atom, e.g., Al,B, Ga, Ti, V, Zr, Fe, Mn, Sn, Zn, Cu and Nb, containing mesoporousmaterials have also been prepared.

The inorganic portion of MCM-41 resembles amorphous silicas rather thancrystalline molecular sieves in terms of the local structure andbonding, but has many peculiar properties. It possesses uniformly sizedmesopores with thin walls (around 10 Angstroms) and shows hydrophobicadsorption behavior.

It has now been discovered that zeolites having the topology of zeolitebeta, in either all-silica form or in a form containing silica and metal(or non-silicon) oxide(s), can be made using the inorganic portion ofordered, mesoporous materials as reagents. The mesoporous materials maybe all-silica, or they may contain silica and metal (or non-silicon)oxide(s), e.g., aluminum oxide. Examples of such mesoporous materialsinclude, but are not limited to, MCM-41 and MCM-48.

The mesoporous materials are used in combination with tetraethylammoniumcation organic templating agent, e.g., tetraethylammonium hydroxide(TEAOH). It has been found that, in order to assure the zeolite beta hasessentially no defect sites, the reaction mixture containing themesoporous material and TEAOH should be in the form of a “dry gel”. Thedry gel is made by impregnating the mesoporous material with an aqueoussolution of TEAOH, allowing the resulting impregnated material to dryfor about one day at room temperature. The thus-impregnated productshould have a molar ratio of water to mesoporous material of about 0.5to about 2, and contain sufficient TEAOH to cause formation of the betastructure. The impregnated material is then subject to crystallizationconditions in an autoclave. The resulting crystalline product can eitherbe calcined to remove the TEAOH, or it can be subjected to theextraction technique described above, thus assuring the product will beessentially defect-free.

If it is desired that the final product contain silicon oxide and ametal (or non-silicon) oxide, the mesoporous starting material cancontain silicon oxide and the desired metal (or non-silicon) oxide.Metal oxides such as aluminum oxide, titanium oxide, vanadium oxide,zinc oxide, zirconium oxide, and magnesium oxide, as well as non-siliconoxides such as boron oxide, can be incorporated into the zeolite betastructure in this manner.

The molecular sieves made by either of these two techniques are highlyhydrophobic. FIG. 2 shows the results of water adsorption isotherms forcalcined all-silica beta zeolite (line 1), all-Si CIT-6 made from MCM-41and subjected to extraction rather than calcination (line 2), andZn-CIT-6 made by extraction (line 3). As can be seen, the wateradsorption capacities of both the all-Si CIT-6 and Zn-CIT-6 aresubstantially lower than that of calcined all-silica beta zeolite.

When used in a catalyst, the molecular sieve can be used in intimatecombination with hydrogenating components, such as tungsten, vanadium,molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noblemetal, such as palladium or platinum, for those applications in which ahydrogenation-dehydrogenation function is desired.

Metals may also be introduced into the molecular sieve by replacing someof the cations in the molecular sieve with metal cations via standardion exchange techniques (see, for example, U.S. Pat. No. 3,140,249issued Jul. 7, 1964 to Plank et al.; U.S. Pat. No. 3,140,251 issued Jul.7, 1964 to Plank et al.; and U.S Pat. No. 3,140,253 issued Jul. 7, 1964to Plank et al.). Typical replacing cations can include metal cations,e.g., rare earth, Group IA, Group IIA and Group VIII metals, as well astheir mixtures. Of the replacing metallic cations, cations of metalssuch as rare earth, Mn, Ca, Mg, Zn, Cd, Pt, Pd, Ni, Co, Ti, Al, Sn, andFe are particularly preferred.

The hydrogen, ammonium, and metal components can be ion-exchanged intothe catalytically active CIT-6. The molecular sieve can also beimpregnated with the metals, or, the metals can be physically andintimately admixed with the molecular sieve using standard methods knownto the art.

Typical ion-exchange techniques involve contacting the syntheticmolecular sieve with a solution containing a salt of the desiredreplacing cation or cations. Although a wide variety of salts can beemployed, chlorides and other halides, acetates, nitrates, and sulfatesare particularly preferred. The molecular sieve is usually calcinedprior to the ion-exchange procedure to remove the organic matter presentin the channels and on the surface, since this results in a moreeffective ion exchange. Representative ion exchange techniques aredisclosed in a wide variety of patents including U.S. Pat. No. 3,140,249issued on Jul. 7, 1994 to Plank et al.; U.S. Pat. No. 3,140,251 issuedon Jul. 7, 1964 to Plank et al.; and U.S. Pat. No. 3,140,253 issued onJul. 7, 1964 to Plank et al.

Following contact with the salt solution of the desired replacingcation, the molecular sieve is typically washed with water and dried attemperatures ranging from 65° C. to about 200° C. After washing, themolecular sieve can be calcined in air or inert gas at temperaturesranging from about 200° C. to about 800° C. for periods of time rangingfrom 1 to 48 hours, or more, to produce a catalytically active productespecially useful in hydrocarbon conversion processes.

Regardless of the cations present in the synthesized form of CIT-6, thespatial arrangement of the atoms which form the basic crystal lattice ofthe molecular sieve remains essentially unchanged.

Catalytically active CIT-6 can be formed into a wide variety of physicalshapes. Generally speaking, the molecular sieve can be in the form of apowder, a granule, or a molded product, such as extrudate having aparticle size sufficient to pass through a 2-mesh (Tyler) screen and beretained on a 400-mesh (Tyler) screen. In cases where the catalyst ismolded, such as by extrusion with an organic binder, the molecular sievecan be extruded before drying, or, dried or partially dried and thenextruded.

Catalytically active CIT-6 can be composited with other materialsresistant to the temperatures and other conditions employed in organicconversion processes. Such matrix materials include active and inactivematerials and synthetic or naturally occurring zeolites as well asinorganic materials such as clays, silica and metal oxides. Examples ofsuch materials and the manner in which they can be used are disclosed inU.S. Pat. No. 4,910,006, issued May 20, 1990 to Zones et al., and U.S.Pat. No. 5,316,753, issued May 31, 1994 to Nakagawa, both of which areincorporated by reference herein in their entirety.

Hydrocarbon Conversion Processes

The catalytically active CIT-6 molecular sieves are useful inhydrocarbon conversion reactions. Hydrocarbon conversion reactions arechemical and catalytic processes in which carbon containing compoundsare changed to different carbon containing compounds. Examples ofhydrocarbon conversion reactions in which catalytically active CIT-6 isexpected to be useful include hydrocracking, dewaxing, catalyticcracking and olefin and aromatics formation reactions. The catalysts arealso expected to be useful in other petroleum refining and hydrocarbonconversion reactions such as polymerizing and oligomerizing olefinic oracetylenic compounds such as isobutylene and butene-1, reforming,isomerizing polyalkyl substituted aromatics (e.g., m-xylene), anddisproportionating aromatics (e.g., toluene) to provide mixtures ofbenzene, xylenes and higher methylbenzenes and oxidation reactions. Alsoincluded are rearrangement. reactions to make various naphthalenederivatives. The catalytically active CIT-6 catalysts may have highselectivity, and under hydrocarbon conversion conditions can provide ahigh percentage of desired products relative to total products.

The catalytically active CIT-6 molecular sieves can be used inprocessing hydrocarbonaceous feedstocks. Hydrocarbonaceous feedstockscontain carbon compounds and can be from many different sources, such asvirgin petroleum fractions, recycle petroleum fractions, shale oil,liquefied coal, tar sand oil, synthetic paraffins from NAO, recycledplastic feedstocks and, in general, can be any carbon containingfeedstock susceptible to zeolitic catalytic reactions. Depending on thetype of processing the hydrocarbonaceous feed is to undergo, the feedcan contain metal or be free of metals, it can also have high or lownitrogen or sulfur impurities. It can be appreciated, however, that ingeneral processing will be more efficient (and the catalyst more active)the lower the metal, nitrogen, and sulfur content of the feedstock.

The conversion of hydrocarbonaceous feeds can take place in anyconvenient mode, for example, in fluidized bed, moving bed, or fixed bedreactors depending on the types of process desired. The formulation ofthe catalyst particles will vary depending on the conversion process andmethod of operation.

Other reactions which can be performed using the catalyst of thisinvention containing a metal, e.g., a Group VIII metal such platinum,include hydrogenation-dehydrogenation reactions, denitrogenation anddesulfurization reactions.

Depending upon the type of reaction which is catalyzed, the molecularsieve may be predominantly in the hydrogen form, partially acidic orsubstantially free of acidity. As used herein, “predominantly in thehydrogen form” means that, after calcination, at least 80% of the cationsites are occupied by hydrogen ions and/or rare earth ions.

The following table indicates typical reaction conditions which may beemployed when using catalysts comprising catalytically active CIT-6 inthe hydrocarbon conversion reactions of this invention. Preferredconditions are indicated in parentheses.

Process Temp., ° C. Pressure LHSV Hydrocracking 175-485  0.5-350 bar0.1-30  Dewaxing 200-475   15-3000 psig 0.1-20  (250-450) (200-3000)(0.2-10)  Aromatics 400-600 atm.-10 bar 0.1-15  formation (480-550) Cat.cracking 127-885 subatm.-¹ 0.5-50  (atm.-5 atm.) Oligomerization 232-649²  0.1-50 atm.^(2,3)  0.2-50²   10-232⁴   —  0.05-20⁵   (27-204)⁴   — (0.1-10)⁵ Paraffins to 100-700   0-1000 psig 0.5-40⁵aromatics Condensation of 260-538  0.5-1000 psig  0.5-50⁵ alcoholsXylene  260-593²  0.5-50 atm.²  0.1-100⁵ isomerization  (315-566)²  (1-5atm)²  (0.5-50)⁵    38-371⁴   1-200 atm.⁴ 0.5-50  ¹Several hundredatmospheres ²Gas phase reaction ³Hydrocarbon partial pressure ⁴Liquidphase reaction ⁵WHSV

Other reaction conditions and parameters are provided below.

Hydrocracking

Using a catalyst which comprises catalytically active CIT-6, preferablypredominantly in the hydrogen form, and a hydrogenation promoter, heavypetroleum residual feedstocks, cyclic stocks and other hydrocrackatecharge stocks can be hydrocracked using the process conditions andcatalyst components disclosed in the aforementioned U.S. Pat. Nos.4,910,006 and 5,316,753.

The hydrocracking catalysts contain an effective amount of at least onehydrogenation component of the type commonly employed in hydrocrackingcatalysts. The hydrogenation component is generally selected from thegroup of hydrogenation catalysts consisting of one or more metals ofGroup VIB and Group VIII, including the salts, complexes and solutionscontaining such. The hydrogenation catalyst is preferably selected fromthe group of metals, salts and complexes thereof of the group consistingof at least one of platinum, palladium, rhodium, iridium, ruthenium andmixtures thereof or the group consisting of at least one of nickel,molybdenum, cobalt, tungsten, titanium, chromium and mixtures thereof.Reference to the catalytically active metal or metals is intended toencompass such metal or metals in the elemental state or in some formsuch as an oxide, sulfide, halide, carboxylate and the like. Thehydrogenation catalyst is present in an effective amount to provide thehydrogenation function of the hydrocracking catalyst, and preferably inthe range of from 0.05 to 25% by weight.

Dewaxing

Catalytically active CIT-6, preferably predominantly in the hydrogenform, can be used to dewax hydrocarbonaceous feeds by selectivelyremoving straight chain paraffins. Typically, the viscosity index of thedewaxed product is improved (compared to the waxy feed) when the waxyfeed is contacted with catalytically active CIT-6 under isomerizationdewaxing conditions.

The catalytic dewaxing conditions are dependent in large measure on thefeed used and upon the desired pour point. Hydrogen is preferablypresent in the reaction zone during the catalytic dewaxing process. Thehydrogen to feed ratio is typically between about 500 and about 30,000SCF/bbl (standard cubic feet per barrel), preferably about 1000 to about20,000 SCF/bbl. Generally, hydrogen will be separated from the productand recycled to the reaction zone. Typical feedstocks include light gasoil, heavy gas oils and reduced crudes boiling above about 350° F.

A typical dewaxing process is the catalytic dewaxing of a hydrocarbonoil feedstock boiling above about 350° F. and containing straight chainand slightly branched chain hydrocarbons by contacting the hydrocarbonoil feedstock in the presence of added hydrogen gas at a hydrogenpressure of about 15-3000 psi with a catalyst comprising catalyticallyactive CIT-6 and at least one Group VIII metal.

The catalytically active CIT-6 hydrodewaxing catalyst may optionallycontain a hydrogenation component of the type commonly employed indewaxing catalysts. See the aforementioned U.S. Pat. Nos. 4,910,006 and5,316,753 for examples of these hydrogenation components.

The hydrogenation component is present in an effective amount to providean effective hydrodewaxing and hydroisomerization catalyst preferably inthe range of from about 0.05 to 5% by weight The catalyst may be run insuch a mode to increase isodewaxing at the expense of crackingreactions.

The feed may be hydrocracked, followed by dewaxing. This type of twostage process and typical hydrocracking conditions are described in U.S.Pat. No. 4,921,594, issued May 1, 1990 to Miller, which is incorporatedherein by reference in its entirety.

Catalytically active CIT-6 may also be utilized as a dewaxing catalystin the form of a layered catalyst. That is, the catalyst comprises afirst layer comprising catalytically active molecular sieve CIT-6 and atleast one Group VIII metal, and a second layer comprising analuminosilicate zeolite which is more shape selective than catalyticallyactive molecular sieve CIT-6. The use of layered catalysts is disclosedin U.S. Pat. No. 5,149,421, issued Sep. 22, 1992 to Miller, which isincorporated by reference herein in its entirety. The layering may alsoinclude a bed of catalytically active CIT-6 layered with a non-zeoliticcomponent designed for either hydrocracking or hydrofinishing.

Catalytically active CIT-6 may also be used to dewax raffinates,including bright stock, under conditions such as those disclosed in U.S.Pat. No. 4,181,598, issued Jan. 1, 1980 to Gillespie et al., which isincorporated by reference herein in its entirety.

It is often desirable to use mild hydrogenation (sometimes referred toas hydrofinishing) to produce more stable dewaxed products. Thehydrofinishing step can be performed either before or after the dewaxingstep, and preferably after. Hydrofinishing is typically conducted attemperatures ranging from about 190° C. to about 340° C. at pressuresfrom about 400 psig to about 3000 psig at space velocities (LHSV)between about 0.1 and 20 and a hydrogen recycle rate of about 400 to1500 SCF/bbl. The hydrogenation catalyst employed must be active enoughnot only to hydrogenate the olefins, diolefins and color bodies whichmay be present, but also to reduce the aromatic content. Suitablehydrogenation catalyst are disclosed in U.S. Pat. No. 4,921,594, issuedMay 1, 1990 to Miller, which is incorporated by reference herein in itsentirety. The hydrofinishing step is beneficial in preparing anacceptably stable product (e.g., a lubricating oil) since dewaxedproducts prepared from hydrocracked stocks tend to be unstable to airand light and tend to form sludges spontaneously and quickly.

Lube oil may be prepared using catalytically active CIT-6. For example,a C₂₀₊ lube oil may be made by isomerizing a C₂₀₊ olefin feed over acatalyst comprising catalytically active CIT-6 in the hydrogen form andat least one Group VIII metal. Alternatively, the lubricating oil may bemade by hydrocracking in a hydrocracking zone a hydrocarbonaceousfeedstock to obtain an effluent. comprising a hydrocracked oil, andcatalytically dewaxing the effluent at a temperature of at least about400° F. and at a pressure of from about 15 psig to about 3000 psig inthe present of added hydrogen gas with a catalyst comprisingcatalytically active CIT-6 in the hydrogen form and at least one GroupVIII metal.

Aromatics Formation

Catalytically active CIT-6 can be used to convert light straight runnaphthas and similar mixtures to highly aromatic mixtures. Thus, normaland slightly branched chained hydrocarbons, preferably having a boilingrange above about 40° C. and less than about 200° C., can be convertedto products having a substantial higher octane aromatics content bycontacting the hydrocarbon feed with a catalyst comprising catalyticallyactive CIT-6. It is also possible to convert heavier feeds into BTX ornaphthalene derivatives of value using a catalyst comprisingcatalytically active CIT-6.

The conversion catalyst preferably contains a Group VIII metal compoundto have sufficient activity for commercial use. By Group VIII metalcompound as used herein is meant the metal itself or a compound thereof.The Group VIII noble metals and their compounds, platinum, palladium,and iridium, or combinations thereof can be used. Rhenium or tin or amixture thereof may also be used in conjunction with the Group VIIImetal compound and preferably a noble metal compound. The most preferredmetal is platinum. The amount of Group VIII metal present in theconversion catalyst should be within the normal range of use inreforming catalysts, from about 0.05 to 2.0 weight percent, preferably0.2 to 0.8 weight percent.

It is critical to the selective production of aromatics in usefulquantities that the conversion catalyst be substantially free ofacidity, for example, by neutralizing the molecular sieve with a basicmetal, e.g., alkali metal, compound. Methods for rendering the catalystfree of acidity are known in the art. See the aforementioned U.S. Pat.Nos. 4,910,006 and 5,316,753 for a description of such methods.

The preferred alkali metals are sodium, potassium, rubidium and cesium.

Catalytic Cracking

Hydrocarbon cracking stocks can be catalytically cracked in the absenceof hydrogen using catalytically active CIT-6, preferably predominantlyin the hydrogen form.

When catalytically active CIT-6 is used as a catalytic cracking catalystin the absence of hydrogen, the catalyst may be employed in conjunctionwith traditional cracking catalysts, e.g., any aluminosilicateheretofore employed as a component in cracking catalysts. Typically,these are large pore, crystalline aluminosilicates. Examples of thesetraditional cracking catalysts are disclosed in the aforementioned U.S.Pat. Nos. 4,910,006 and 5,316,753. When a traditional cracking catalyst(TC) component is employed, the relative weight ratio of the TC to thecatalytically active CIT-6 is generally between about 1:10 and about500:1, desirably between about 1:10 and about 200:1, preferably betweenabout 1:2 and about 50:1, and most preferably is between about 1:1 andabout 20:1. The novel molecular sieve and/or the traditional crackingcomponent may be further ion exchanged with rare earth ions to modifyselectivity.

The cracking catalysts are typically employed with an inorganic oxidematrix component. See the aforementioned U.S. Pat. Nos. 4,910,006 and5,316,753 for examples of such matrix components.

Alkylation and Transalkylation

Catalytically active CIT-6 can be used in a process for the alkylationor transalkylation of an aromatic hydrocarbon. The process comprisescontacting the aromatic hydrocarbon with a C₂ to C₁₆ olefin alkylatingagent or a polyalkyl aromatic hydrocarbon transalkylating agent, underat least partial liquid phase conditions, and in the presence of acatalyst comprising catalytically active CIT-6.

Catalytically active CIT-6 can also be used for removing benzene fromgasoline by alkylating the benzene as described above and removing thealkylated product from the gasoline.

For high catalytic activity, the catalytically active CIT-6 molecularsieve should be predominantly in its hydrogen ion form. It is preferredthat, after calcination, at least 80% of the cation sites are occupiedby hydrogen ions and/or rare earth ions.

Examples of suitable aromatic hydrocarbon feedstocks which may bealkylated or transalkylated by the process of the invention includearomatic compounds such as benzene, toluene and xylene. The preferredaromatic hydrocarbon is benzene. There may be occasions wherenaphthalene derivatives may be desirable. Mixtures of aromatichydrocarbons may also be employed.

Suitable olefins for the alkylation of the aromatic hydrocarbon arethose containing 2 to 20, preferably 2 to 4, carbon atoms, such asethylene, propylene, butene-1, trans-butene-2 and cis-butene-2, ormixtures thereof. There may be instances where pentenes are desirable.The preferred olefins are ethylene and propylene. Longer chain alphaolefins may be used as well.

When transalkylation is desired, the transalkylating agent is apolyalkyl aromatic hydrocarbon containing two or more alkyl groups thateach may have from 2 to about 4 carbon atoms. For example, suitablepolyalkyl aromatic hydrocarbons include di-, tri- and tetra-alkylaromatic hydrocarbons, such as diethylbenzene, triethylbenzene,diethylmethylbenzene (diethyltoluene), di-isopropylbenzene,di-isopropyltoluene, dibutylbenzene, and the like. Preferred polyalkylaromatic hydrocarbons are the dialkyl benzenes. A particularly preferredpolyalkyl aromatic hydrocarbon is di-isopropylbenzene.

When alkylation is the process conducted, reaction conditions are asfollows. The aromatic hydrocarbon feed should be present instoichiometric excess. It is preferred that molar ratio of aromatics toolefins be greater than four-to-one to prevent rapid catalyst fouling.The reaction temperature may range from 100° F. to 600° F., preferably250° F. to 45° F. The reaction pressure should be sufficient to maintainat least a partial liquid phase in order to retard catalyst fouling.This is typically 50 psig to 1000 psig depending on the feedstock andreaction temperature. Contact time may range from 10 seconds to 10hours, but is usually from 5 minutes to an hour. The weight hourly spacevelocity (WHSV), in terms of grams (pounds) of aromatic hydrocarbon andolefin per gram (pound) of catalyst per hour, is generally within therange of about 0.5 to 50.

When transalkylation is the process conducted, the molar ratio ofaromatic hydrocarbon will generally range from about 1:1 to 25:1, andpreferably from about 2:1 to 20:1. The reaction temperature may rangefrom about 100° F. to 600° F., but it is preferably about 250° F. to450° F. The reaction pressure should be sufficient to maintain at leasta partial liquid phase, typically in the range of about 50 psig to 1000psig, preferably 300 psig to 600 psig. The weight hourly space velocitywill range from about 0.1 to 10. U.S. Pat. No. 5,082,990 issued on Jan.21, 1992 to Hsieh, et al. describes such processes and is incorporatedherein by reference.

Isomerization of Olefins

Catalytically active CIT-6 can be used to isomerize olefins. The feedstream is a hydrocarbon stream containing at least one C₄₋₆ olefin,preferably a C₄₋₆ normal olefin, more preferably normal butene. Normalbutene as used in this specification means all forms of normal butene,e.g., 1-butene, cis-2-butene, and trans-2-butene. Typically,hydrocarbons other than normal butene or other C₄₋₆ normal olefins willbe present in the feed stream. These other hydrocarbons may include,e.g., alkanes, other olefins, aromatics, hydrogen, and inert gases.

The feed stream typically may be the effluent from a fluid catalyticcracking unit or a methyl-tert-butyl ether unit. A fluid catalyticcracking unit effluent typically contains about 40-60 weight percentnormal butenes. A methyl-tert-butyl ether unit effluent typicallycontains 40-100 weight percent normal butene. The feed stream preferablycontains at least about 40 weight percent normal butene, more preferablyat least about 65 weight percent normal butene. The terms iso-olefin andmethyl branched iso-olefin may be used interchangeably in thisspecification.

The process is carried out under isomerization conditions. Thehydrocarbon feed is contacted in a vapor phase with a catalystcomprising the catalytically active CIT-6. The process may be carriedout generally at a temperature from about 625° F. to about 950° F.(329-510° C.), for butenes, preferably from about 700° F. to about 900°F. (371-482° C.), and about 350° F. to about 650° F. (177-343° C.) forpentenes and hexenes. The pressure ranges from subatmospheric to about200 psig, preferably from about 15 psig to about 200 psig, and morepreferably from about 1 psig to about 150 psig.

The liquid hourly space velocity during contacting is generally fromabout 0.1 to about 50 hr⁻¹, based on the hydrocarbon feed, preferablyfrom about 0.1 to about 20 hr⁻¹, more preferably from about 0.2 to about10 hr⁻¹, most preferably from about 1 to about 5 hr⁻¹. Ahydrogen/hydrocarbon molar ratio is maintained from about 0 to about 30or higher. The hydrogen can be added directly to the feed stream ordirectly to the isomerization zone. The reaction is preferablysubstantially free of water, typically less than about two weightpercent based on the feed. The process can be carried out in a packedbed reactor, a fixed bed, fluidized bed reactor, or a moving bedreactor. The bed of the catalyst can move upward or downward. The molepercent conversion of, e.g., normal butene to iso-butene is at least 10,preferably at least 25, and more preferably at least 35.

Conversion of Paraffins to Aromatics

Catalytically active CIT-6 can be used to convert light gas C₂-C₆paraffins to higher molecular weight hydrocarbons including aromaticcompounds. Preferably, the molecular sieve will contain a catalyst metalor metal oxide wherein said metal is selected from the group consistingof Groups IB, IIB, VIII and IIIA of the Periodic Table. Preferably, themetal is gallium, niobium, indium or zinc in the range of from about0.05 to 5% by weight.

Xylene Isomerization

Catalytically active CIT-6 may also be useful in a process forisomerizing one or more xylene isomers in a Cs aromatic feed to obtainortho-, meta- and para-xylene in a ratio approaching the equilibriumvalue. In particular, xylene isomerization is used in conjunction with aseparate process to manufacture para-xylene. For example, a portion ofthe para-xylene in a mixed C₈ aromatics stream may be recovered bycrystallization and centrifugation. The mother liquor from thecrystallizer is then reacted under xylene isomerization conditions torestore ortho-, meta- and para-xylenes to a near equilibrium ratio. Atthe same time, part of the ethylbenzene in the mother liquor isconverted to xylenes or to products which are easily separated byfiltration. The isomerate is blended with fresh feed and the combinedstream is distilled to remove heavy and light by-products. The resultantC₈ aromatics stream is then sent to the crystallizer to repeat thecycle.

Optionally, isomerization in the vapor phase is conducted in thepresence of 3.0 to 30.0 moles of hydrogen per mole of alkylbenzene(e.g., ethylbenzene). If hydrogen is used, the catalyst should compriseabout 0.1 to 2.0 wt. % of a hydrogenation/dehydrogenation componentselected from Group VIII (of the Periodic Table) metal component,especially platinum or nickel. By Group VIII metal component is meantthe metals and their compounds such as oxides and sulfides.

Optionally, the isomerization feed may contain 10 to 90 wt. % of adiluent such as toluene, trimethylbenzene, naphthenes or paraffins.

Oligomerization

It is expected that catalytically active CIT-6 can also be used tooligomerize straight and branched chain olefins having from about 2 to21 and preferably 2-5 carbon atoms. The oligomers which are the productsof the process are medium to heavy olefins which are useful for bothfuels, i.e., gasoline or a gasoline blending stock and chemicals.

The oligomerization process comprises contacting the olefin feedstock inthe gaseous or liquid phase with a catalyst comprising catalyticallyactive CIT-6.

The molecular sieve can have the original cations associated therewithreplaced by a wide variety of other cations according to techniques wellknown in the art. Typical cations would include hydrogen, ammonium andmetal cations including mixtures of the same. Of the replacing metalliccations, particular preference is given to cations of metals such asrare earth metals, manganese, calcium, as well as metals of Group II ofthe Periodic Table, e.g., zinc, and Group VIII of the Periodic Table,e.g., nickel. One of the prime requisites is that the molecular sievehave a fairly low amortization activity, i.e., in which the amount ofaromatics produced is not more than about 20% by weight. This isaccomplished by using a molecular sieve with controlled acid activity[alpha value] of from about 0.1 to about 120, preferably from about 0.1to about 100, as measured by its ability to crack n-hexane.

Alpha values are defined by a standard test known in the art, e.g., asshown in U.S. Pat. No. 3,960,978 issued on Jun. 1, 1976 to Givens et al.which is incorporated totally herein by reference. If required, suchmolecular sieves may be obtained by steaming, by use in a conversionprocess or by any other method which may occur to one skilled in thisart.

Condensation of Alcohols

Catalytically active CIT-6 can be used to condense lower aliphaticalcohols having 1 to 10 carbon atoms to a gasoline boiling pointhydrocarbon product comprising mixed aliphatic and aromatic hydrocarbon.The process disclosed in U.S. Pat. No. 3,894,107, issued Jul. 8, 1975 toButter et al., describes the process conditions used in this process,which patent is incorporated totally herein by reference.

The catalyst may be in the hydrogen form or may be base exchanged orimpregnated to contain ammonium or a metal cation complement, preferablyin the range of from about 0.05 to 5% by weight. The metal cations thatmay be present include any of the metals of the Groups I through VIII ofthe Periodic Table. However, in the case of Group IA metals, the cationcontent should in no case be so large as to effectively inactivate thecatalyst, nor should the exchange be such as to eliminate all acidity.There may be other processes involving treatment of oxygenatedsubstrates where a basic catalyst is desired.

Other Uses for CIT-6

CIT-6 can-also be used as an adsorbent with high selectivities based onmolecular sieve behavior and also based upon preferential hydrocarbonpacking within the pores.

CIT-6 is a hydrophobic material that can be used to remove some organiccompounds from water.

CIT-6 may also be used for the catalytic reduction of the oxides ofnitrogen in a gas stream. Typically, the gas stream also containsoxygen, often a stoichiometric excess thereof Also, the CIT-6 maycontain a metal or metal ions within or on it which are capable ofcatalyzing the reduction of the nitrogen oxides. Examples of such metalsor metal ions include copper, cobalt and mixtures thereof.

One example of such a process for the catalytic reduction of oxides ofnitrogen in the presence of a molecular sieve is disclosed in U.S. Pat.No. 4,297,328, issued Oct. 27, 1981 to Ritscher et al., which isincorporated by reference herein. There, the catalytic process is thecombustion of carbon monoxide and hydrocarbons and the catalyticreduction of the oxides of nitrogen contained in a gas stream, such asthe exhaust gas from an internal combustion engine. The molecular sieveused is metal ion-exchanged, doped or loaded sufficiently so as toprovide an effective amount of catalytic copper metal or copper ionswithin or on the molecular sieve. In addition, the process is conductedin an excess of oxidant, e.g., oxygen.

Oxidation

Titanium-containing CIT-6 may be used as a catalyst in oxidationreactions.

The oxidizing agent employed in the oxidation processes of thisinvention is a hydrogen peroxide source such as hydrogen peroxide (H₂O₂)or a hydrogen peroxide precursor (i.e., a compound which under theoxidation reaction conditions is capable of generating or liberatinghydrogen peroxide).

The amount of hydrogen peroxide relative to the amount of substrate isnot critical, but must be sufficient to cause oxidation of at least someof the substrate. Typically, the molar ratio of hydrogen peroxide tosubstrate is from about 100:1 to about 1:100, preferably 10:1 to about1:10. When the substrate is an olefin containing more than onecarbon-carbon double bond, additional hydrogen peroxide may be required.Theoretically, one equivalent of hydrogen peroxide is required tooxidize one equivalent of a mono-unsaturated substrate, but it may bedesirable to employ an excess of one reactant to optimize selectivity tothe epoxide. In particular, the use of a moderate to large excess (e.g.,50 to 200%) of olefin relative to hydrogen peroxide may be advantageousfor certain substrates.

If desired, a solvent may additionally be present during the oxidationreaction in order to dissolve the reactants other than the Ti-containingCIT-6, to provide better temperature control, or to favorably influencethe oxidation rates and selectivities. The solvent, if present, maycomprise from 1 to 99 weight percent of the total oxidation reactionmixture and is preferably selected such that it is a liquid at theoxidation reaction temperature. Organic compounds having boiling pointsat atmospheric pressure of from about 50° C. to about 150° C. aregenerally preferred for use. Excess hydrocarbon may serve. as a solventor diluent. Illustrative examples of other suitable solvents include,but are not limited to, ketones (e.g., acetone, methyl ethyl ketone,acetophenone), ethers (e.g., tetrahydrofuran, butyl ether), nitrites(e.g., acetonitrile), aliphatic and aromatic hydrocarbons, halogenatedhydrocarbons, and alcohols (e.g., methanol, ethanol, isopropyl alcohol,t-butyl alcohol, alpha-methyl benzyl alcohol, cyclohexanol). More thanone type of solvent may be utilized. Water may also be employed as asolvent or diluent.

The reaction temperature is not critical, but should be sufficient toaccomplish substantial conversion of the substrate within a reasonablyshort period of time. It is generally advantageous to carry out thereaction to achieve as high a hydrogen peroxide conversion as possible,preferably at least about 50%, more preferably at least about 90%, mostpreferably at least about 95%, consistent with reasonable selectivities.The optimum reaction temperature will be influenced by catalystactivity, substrate reactivity, reactant concentrations, and type ofsolvent employed, among other factors, but typically will be in a rangeof from about 0° C. to about 150° C. (more preferably from about 25° C.to about 120° C). Reaction or residence times from about one minute toabout 48 hours (more desirably from about ten minutes to about eighthours) will typically be appropriate, depending upon theabove-identified variables. Although subatmospheric pressures can beemployed, the reaction is preferably performed at atmospheric or atelevated pressure (typically, between one and 100 atmospheres),especially when the boiling point of the substrate is below theoxidation reaction temperature. Generally, it is desirable to pressurizethe reaction vessel sufficiently to maintain the reaction components asa liquid phase mixture. Most (over 50%) of the substrate shouldpreferably be present in the liquid phase.

The oxidation process of this invention may be carried out in a batch,continuous, or semi-continuous manner using any appropriate type ofreaction vessel or apparatus such as a fixed bed, transport bed,fluidized bed, stirred slurry, or CSTR reactor. The reactants may becombined all at once or sequentially. For example, the hydrogen peroxideor hydrogen peroxide precursor may be added incrementally to thereaction zone. The hydrogen peroxide could also be generated in situwithin the same reactor zone where oxidation is taking place.

Once the oxidation has been carried out to the desired degree ofconversion, the oxidized product may be separated and recovered from thereaction mixture using any appropriate technique such as fractionaldistillation, extractive distillation, liquid-liquid extraction,crystallization, or the like.

Additional details for oxidation reactions are disclosed in U.S. Pat.No. 5,869,706, issued Feb. 9, 1999 to Dartt and Davis, which isincorporated herein by reference in its entirety.

Vanadium-containing CIT-6 may be used as a catalyst in theoxidation/dehydrogenation of hydrocarbons. For example,vanadium-containing CIT-6 may be used to partially (or completely)oxidize hydrocarbons in the presence of oxygen (air) or hydrogenperoxide. The oxidation may either be complete, i.e., oxidizing thehydrocarbon to carbon dioxide, or partial, as in the oxidation ofpropane to propylene. The reaction is conducted under conditions thatyield the desired degree of oxidation, and are known in the art.

EXAMPLES

The following examples demonstrate but do not limit the presentinvention.

Example 1-25 Synthesis of Zn-CIT-6

Zn-CIT-6 reaction mixtures are prepared by the following method. Afterthe organic and inorganic cations are dissolved in distilled water, zincacetate dihydrate is added. Next, silica is added and the mixture isstirred for two hours.

The starting mixtures are each charged into Teflon-lined, stainlessautoclaves and heated statically in convection ovens. The products arecollected by vacuum filtration, washed with distilled water, and driedin air at room temperature. In order to remove the occluded organicmolecules, the product is heated in air to 540° C. within six hours andmaintained at this temperature for six hours. An as-made Zn-CIT-6 istreated with 1 M aqueous ammonium nitrate solution at 80° C. for tenhours. The treated sample is recovered by vacuum filtration and washedwith distilled water. This procedure is repeated four times. The finalmaterial is dried in air at room temperature.

Using the above procedure, the products indicated below are made from areaction mixture having the following composition:

bLiOH:cTEAOH:aZn(CH₃COO).2H₂O:SiO2:dH2O

Example Temp. No. b c a D (° C.) Days Product 1 0.05 0.55 0.03 30 150 3CIT-6 2 0.05 0.55 0.03 30 150 5 CIT-6 + VPI-8 3 0.05 0.55 0.03 30 150 7VPI-8 4 0.2 0.4 0.03 30 150 3 VPI-8 5 0.05 0.55 0.03 30 175 2 Amorph. 60.05 0.55 0.03 30 175 3 VPI-8 7 0.05 0.55 0.03 30 135 9 CIT-6 8 0.050.55 0.03 30 135 15 CIT-6 9 0.05 0.55 0.03 30 135 18 VPI-8 10 0.05 0.450.03 30 150 6 VPI-8 11 0.05 0.55 0.03 30 150 4 CIT-6 12 0.05 0.55 0.0330 150 6 VPI-8 13 0.05 0.6 0.03 30 150 4 CIT-6 14 0.05 0.6 0.03 30 15029 VPI-8 + small amnt. CIT-6 15 0.05 0.65 0.03 30 150 4 CIT-6 16 0.050.65 0.03 30 150 17 CIT-6 + small amnt. VPI-8 17 0.05 0.65 0.03 40 150 4CIT-6 18 0.05¹ 0.65 0.03 30 150 14 Amorph. 19 0.05 0.6 0.01 30 150 11Amorph. + small amnt. MFI 20 0.05 0.6 0.01 30 150 18 MFI 21 0.05 0.55 —30 150 5 MTW 22 0.05 0.65 0.05 30 150 4 CIT-6 + small amnt. VPI-8 230.02 0.6 0.03 30 150 17 Amorph. 24 0.1 0.6 0.03 30 150 4 Unknown + CIT-625^(2,3) 0.05 0.7 0.03 30 150 4 CIT-6 ¹NaOH used instead of LiOH.²Silica source is Cab-O-Sil M5 fumed silica. All others are HS-30.³Milky white mixture heated at 80° C. for three hours to get a clearsolution.

The results above demonstrate that (1) too long a reaction time canproduce VPI-8 instead of Zn-CIT-6 (Ex. 3,9, 12, 14 and 17); (2) too higha reaction temperature may not produce Zn-CIT-6 (Ex. 5 and 6); (3) thepresence and concentration of lithium is critical to formation ofZn-CIT-6 (Ex. 4, 18 and 22); and the presence and concentration of zincis critical to formation of Zn-CIT-6 (Ex. 19, 20 and 21).

Example 26 Synthesis of Zincoaluminosilicate CIT-6

A solution of tetraethylammonium hydroxide (4.10 grams of a 35 wt.%solution) is added to 3.34 grams of water. To this is added 0.018 gramof LiOH, 0.098 gram of zinc acetate dihydrate, and 0.056 gram ofAl(NO₃)₃.9H₂O and the resulting mixture stirred. Three grams of LudoxHS-30 silica is added and the resulting mixture stirred for two hours.The resulting solution is charged into a Teflon-lined autoclave, andheated (statically) at 150° C. for four days. The product was CIT-6containing both zinc and aluminum in the crystal framework.

Example 27 Extraction of TEA and Zinc

The TEA and zinc are extracted from the CIT-6 prepared in Example 26 bycontacting 0.1 gram of the aluminozincosilicate CIT-6 with a solutioncontaining 6 ml acetic acid, 1 ml pyridine and 10 ml water at 135° C.for two days. The TEA and zinc are extracted from the CIT-6, but thealuminum remains in the crystal framework, as shown by ²⁷Al NMR.

Example 28 Cyclohexane Adsorption

The adsorption amount of vapor-phase cyclohexane (99.5%, EM) forZn-CIT-6 is measured at 25° C. using a McBaine-Bakr balance. Prior tothe adsorption experiment, calcined samples of CIT-6 are dehydrated at350° C. under vacuum for five hours. The saturation pressure, P₀, ofcyclohexane is 97.5 mm Hg. The adsorption is performed at a cyclohexanepressure of 30 mm Hg. The amount of adsorbed cyclohexane of the Zn-CIT-6sample is 0.16 ml/g. This value is slightly smaller than that ofaluminosilicate beta (0.22 ml/g).

Example 29 Extraction of TEA and Zinc

The TEA and zinc are extracted from Zn-CIT-6 by contacting 0.1 gram ofCIT-6 with a solution containing 6 ml acetic acid, 0.1 ml pyridine and10 ml water at 60° C. for three days.

Example 30 Insertion of Aluminum

Aluminum is inserted into the product of Example 29 by contacting theproduct with an aqueous solution of aluminum nitrate at a 1:2:50 weightratio of Zn-CIT-6:aluminum nitrate:water at 80° C. for one day.

Example 31 Insertion of Titanium

Titanium is inserted into the product of Example 29 by contacting theproduct with 1.5 ml 1M TiCl₄ toluene solution and 10 ml toluene at 80°C. for 12 hours under nitrogen atmosphere. After treatment, the sampleis filtrated, washed with acetone and dried. UV analysis of theresultant product shows that titanium is inserted in the product.

Example 32 Preparation of Pd-Zn-CIT-6

2.84 grams of Zn-CIT-6 synthesized as in Example 1 is calcined to 540°C. in a mixture of air and nitrogen, and subsequently ion-exchanged oncewith ammonium nitrate at 85° C. for two hours, recovered and dried to300° C. Pd acetylacetonate (0.0286 gms) in toluene (2.25 ml) is admittedinto a sealed bottle in which the heated Zn-CIT-6 has been placed. Thisprovides for some vacuum at room temperature. The bottle is manuallyshaken while the solution is admitted by syringe. The wetted solid isallowed to stand overnight. Next the material is calcined to 425° C. inair.

Example 33 Catalytic Activity

The Pd-Zn-CIT-6 prepared in Example 30 is loaded as 24-40 mesh particlesinto a stainless steel reactor. 0.50 Gram is packed into a ⅜ inchstainless steel tube with alundum on both sides of the zeolite bed. ALindburg furnace is used to heat the reactor tube. Helium is introducedinto the reactor tube at 10 cc/min. and at atmospheric pressure. Thereactor is heated to about 372° C., and a 50/50 (w/w) feed of n-hexaneand 3-methylpentane is introduced into the reactor at a rate of 8μl/min. Feed delivery is made via a Brownlee pump. Direct sampling intoa gas chromatograph begins after 10 minutes of feed introduction. At800° F. (427° C.) and 10 minutes on stream the catalyst gives 47%conversion with the products being about ⅓ aromatics, ⅓ isomerized C₆and a third olefins from dehydrogenation. There is a few percent crackedproduct. The is no preference for reaction of either isomer.

Example 34 Synthesis of All-Si CIT-6 From All-silica Mesoporous Material

MCM-41 is prepared using the following gel composition where C₁₆ TMA ishexadecyltrimethylammonium:

SiO₂/0.39 Na₂O/0.26 (C₁₆TMA)₂O/0.14 H₂SO₄/0.51 HBr/62.53 H₂O

The gel is placed in an autoclave at 120° C. for three days. Theresulting MCM-41 crystals are recovered and calcined at 540° C. for tenhours.

The calcined MCM-41 (0.1 gram) is impregnated with 0.3 gram of 35 wt. %TEAOH aqueous solution and dried at room temperature for one day(TEAOH/Si=0.4, H₂O/Si=˜2). The resulting powder is charged into anautoclave and heated at 150° C. for seven days. The product isall-silica zeolite beta.

0.1 Gram of the all-silica zeolite beta (still containing TEAOH) istreated with a mixture of 6 ml acetic acid and 10 ml water at 135° C.for two days. Almost all of the TEAOH is removed from the material, andit retains the beta zeolite structure. The resulting product is highlyhydrophobic.

Example 35 Synthesis of Si-MCM-41

Si-MCM-41 materials (Si-1-MCM-41) are prepared by adding 2.4 grams of 29wt. % NH₄OH solution (EM) to 26.4 grams of 29 wt. %hexadecyltrimethylammonium chloride (C₁₆TMACl) solution. This solutionis combined with 2.3 grams of tetramethylammonium hydroxide pentahydrate(TMAOH.5H₂O), 20 grams of tetramethylammonium silicate (10 wt. % SiO₂,TMA/Si=0.5) and 4.5 grams of fumed silica (Cab-O-Sil M-5 from Cabot)under stirring. The composition of the resulting gel is:

SiO₂:0.11 (C₁₆TMA)₂O:0.09 (NH₄)₂O:0.11 HCl:19.3 H₂O.

The reaction mixture is charged into a Teflon-lined, stainless steelautoclave and heated statically at 140° C. for three days. The productis collected by vacuum filtration, washed with water and dried in air atroom temperature. In order to remove occluded molecules, the as-madesample is calcined in air at 550° C. within six hours and maintained atthis temperature for six hours. The product is identified as MCM-41 anddesignated Si-1-MCM-41.

Example 36 Synthesis of Si-MCM-41

Concentrated H₂SO₄ (1.2 grams) is added dropwise to 20 grams of sodiumsilicate (10.8 wt. % Na₂O, 27.0 wt. % SiO₂ and 62.2 wt. % H₂O) in 42.8grams of water under stirring. Next, 16.8 grams of C₁₆TMABr in 50.3grams of water is added to the solution and the resulting mixture isstirred for two hours. The resulting gel has the composition:

SiO₂:0.26 (C₁₆TMA)₂O:0.39 Na₂O:0.14 H₂SO₄:0.51 HBr:62.5 H₂O.

The reaction mixture is charged into a Teflon-lined, stainless steelautoclave and heated statically at 120° C. for three days. The productis collected by vacuum filtration, washed with water and dried in air atroom temperature and calcined in air at 550° C. within six hours andmaintained at this temperature for six hours to remove the organicmolecules. The organic molecules occluded in the pores of the materialare also removed by contacting the as-made sample with 1M HCl solutionin diethyl ether at room temperature. The product is identified asMCM-41 and designated Si-2-MCM-41.

Example 37 Synthesis of MCM-48

NaOH (0.8 gram) is dissolved in 44 grams of water. To this solution isadded 8.89 grams of C₁₆TMABr and finally 8.33 grams of TEOS is added toit. The resulting mixture is stirred at room temperature for two hours.The mixture has the following composition:

SiO₂:0.61 C₁₆TMABr:60 H₂O:0.5 NaOH:4 EtOH.

The reaction mixture is charged into a Teflon-lined, stainless steelautoclave and heated statically at 105° C. for three days. The productis collected by vacuum filtration, washed with water and dried in air atroom temperature and calcined in air at 550° C. within six hours andmaintained at this temperature for six hours to remove the organicmolecules. The product is identified as MCM-48.

Example 38 Synthesis of Al-Containing MCM-41

2.4 Grams of 29 wt. % NH₄OH solution is added to 26.4 grams of 29 wt. %C₁₆TMACl solution. To this, 0.37 gram of sodium aluminate (54 wt. %Al₂O₃, 41 wt. % Na₂O, 5 wt. % H₂O) is added and the solution is combinedwith 2.3 grams of TMAOH.5H₂O, 20 grams of tetramethylammonium silicate(10 wt. % SiO₂, TMA/Si=0.5) and 4.5 grams of fumed silica (Cab-O-SilM-5) under stirring. The resulting gel composition is:

 SiO₂:0.02 Al₂O₃:0.02 Na₂O:0.11 (C₁₆TMA)₂O:0.13 (TMA)₂O:0.09(NH₄)₂O:0.22 HCl:19.3 H₂O.

The reaction mixture is charged into a Teflon-lined, stainless steelautoclave and heated statically at 135° C. for three days. The productis collected by vacuum filtration, washed with water and dried in air atroom temperature. In order to remove the occluded molecules, the as-madesample is calcined in air at 550° C. within six hours and maintained atthis temperature for six hours. The product is identified as MCM-41containing aluminum in its framework, and is designated Al-MCM-41.

Example 39 Synthesis of B-Containing MCM-41

A mixture of 1 gram of fumed silica (Cab-O-Sil M5) and 6.4 grams ofwater are mixed under vigorous stirring. After ten minutes of mixing, asolution of 3.3 grams of C₁₆TMABr in 21.7 grams of water is added tothis slurry. After another ten minutes of stirring, a third solutioncontaining 2.9 grams of tetramethylammonium silicate solution (10 wt. %SiO₂, TMA/Si=0.5) and 1.4 grams of sodium silicate is added to theslurry. H₃BO₃ (0.034 gram) is added and the mixing continued for 30minutes. The resulting gel has the composition:

SiO₂:0.02 H₃BO₃:0.16 C₁₆ TMABr:0.085 Na₂O:63 H₂O.

The reaction mixture is charged into a Teflon-lined, stainless steelautoclave and heated statically at 100° C. for one day. The product iscollected by vacuum filtration, washed with water and dried in air atroom temperature and calcined under nitrogen for temperatures up to 550°C. within six hours and maintained at this temperature for two hoursbefore slowly switching from nitrogen to air. After an additional fourhours at 500° C., the sample is cooled to room temperature. The productis identified as MCM-41 containing boron in its framework, and isdesignated B-MCM-41.

Example 40 Synthesis of V-Containing MCM-41

6.24 Grams of tetraethyl orthosilicate (TEOS), 0.16 gram of vanadylacetylacetonate, 9 grams of ethanol, and 1.8 of isopropyl alcohol aremixed together (Solution A). A second solution (B) contains 1.5 grams ofdodecylamine (C₁₂A), 0.6 gram of 1 N HCl and 19 grams of water. SolutionA is added slowly to Solution B under vigorous stirring. The resultingreaction mixture has the following composition:

 SiO₂:0.02VO(acac)₂:0.27C₁₂A:0.02 HCl:36H₂O:10.5EtOH:1 iPrOH.

The mixture is stirred at room temperature for 12 hours. The product iscollected by vacuum filtration, washed with water and dried in air atroom temperature and calcined in air at 550° C. within six hours andmaintained at this temperature for six hours to remove organicmolecules. The product is identified as MCM-41 containing vanadium inits fiamework, and is designated V-MCM-41.

Example 41 Synthesis of Zr-Containing MCM-41

Solution A is prepared by mixing 10.42 grams of TEOS, 0.47 gram ofzirconium propoxide (70 wt. % solution in 1-propanol). A second solution(B) contains 4 grams of octadecylamine (C₁₈A), 15 grams of ethanol and27 grams of water. Solution A is added slowly to Solution B undervigorous stirring. The resulting reaction mixture has the followingcomposition:

SiO₂:0.02ZrO₂:0.3C₁₈A:30H₂O:10.5EtOH:2.5PrOH.

The mixture is stirred at room temperature for 12 hours. The product iscollected by vacuum filtration, washed with water and dried in air atroom temperature and calcined in air at 550° C. within six hours andmaintained at this temperature for six hours to remove organicmolecules. The product is identified as MCM-41 containing zirconium inits framework, and is designated Zr-MCM-41.

Example 42 Synthesis of Zn-Containing MCM-41

0.18 Gram of zinc acetate dihydrate (Zn(OAc)₂H₂O) and 0.8 gram of NaOHare dissolved in 44 grams of water. 8.89 Grams of C₁₆TMABr is added tothis solution and finally 8.33 grams of TEOS is added. The resultingmixture is stirred at room temperature for two hours. The reactionmixture has the following composition:

SiO₂:0.02Zn(OAc)₂:0.61C₁₆TMABr:60 H₂O:0.5NaOH:4EtOH

The reaction mixture was charged into a Teflon-line, stainless steelautoclave and heated statically at 105° C. for three days. The productis collected by vacuum filtration, washed with water and dried in air atroom temperature and calcined in air at 550° C. within six hours andmaintained at this temperature for six hours to remove organicmolecules. The product is identified as MCM-41 containing zinc in itsframework, and is designated Zn-MCM-41.

Examples 43-49 Synthesis of CIT-6 from Mesoporous Materials

Calcined, mesoporous materials are each in turn impregnated with 35 wt.% TEAOH aqueous solution and dried at room temperature for 12 hours. Theresulting powder is charged into a Teflon-lined autoclave and heated at150° C. statically. The product is washed with distilled water and driedin air at room temperature. In order to remove the occluded molecules,the as-made sample is calcined in air at 550° C. within six hours andmaintained at this temperature for six hours. The organic moleculesoccluded in the pores of the as-made sample are also removed bycontacting the as-made sample with acetic acid at 135° C. for two days.

A typical procedure is as follows: 0.1 gram of calcined Si-MCM-41 isimpregnated with 0.3 gram of 35 wt. % TEAOH aqueous solution(TEAOH/Si=0.4) and dried at room temperature for 12 hours (H₂O/SiO₂molar ratio is about 1.5). The resulting powder is heated at 150° C. forone week in an autoclave. The yield of crystalline solid aftercalcination is about 80%. Conditions for specific materials are shown inthe table below.

Impreg- Exam- Non-Si Atom nated ple Containing TEAOH/ Num- Mesoporous Siber Material^((a)) Ratio Conditions Result^((a)) 43 Al-MCM-41 0.4 150°C. × 7 days Al-Beta (26) (26) 44 B-MCM-41 (54) 0.4 150° C. × 7 daysB-Beta (62) 45 Ti-MCM-41 0.4 150° C. × 7 days Ti-Beta (47) (47) 46Si-MCM-41 0.4 + 150° C. × 7 days Si-Beta (63) Ti (0.02) 47 V-MCM-41 0.4150° C. × 7 days V-Beta (148) (59) 48 Zr-MCM-41 0.4 150° C. × 7 daysZr-Beta (73) (47) 49 Zn-MCM-41 0.4 150° C. × 7 days Zn-Beta (30) (a)Values in parentheses are the Si/Y molar ratios (Y = Al, B, Ti, V, Zr orZn) in the as-made product, measured by elemental analysis.

The as-made materials are then calcined to remove the TEA cations.

Example 50 Synthesis of Ti-Containing CIT-6

Calcined Si-MCM-41 is impregnated with a solution containing titaniumtetraisopropoxide (Ti/Si=0.02) and a 35 wt. % aqueous solution of TEAOH(TEA/Si=0.4). The impregnated solid is treated as described above inExamples 43-49. The resulting product is CIT-6 containing titanium inits framework.

The results above clearly indicate that a highly crystallineall-Si-CIT-6 is formed from Si-MCM-41 using TEAOH as the organictemplate (or structure directing agent). When Na⁺ was added to thereaction mixture, it was found that all-Si-CIT-6 is formed faster thanin the absence of Na⁺. It was also found that when fumed silica was usedas the silica source, only amorphous phases were obtained, even if Na⁺is added. Conventional hydrothermal reaction (H₂O/Si=20) yields onlyamorphous products as well. When using MCM-48 as a silica source,all-Si-CIT-6 is also formed. These data indicate that mesoporous silicassuch as MCM-41 and MCM-48 can be used to synthesize all-Si-CIT-6, thatNa⁺ cations promote the conversion to all-Si-CIT-6 and that themesoporous materials can also be used to prepare CIT-6.

What is claimed is:
 1. A method of removing a tetraethylammonium organictemplate from the pores of a molecular sieve, said molecular sievecomprising silicon oxide and an oxide selected from zinc oxide, aluminumoxide, boron oxide, gallium oxide, iron oxide, titanium oxide, vanadiumoxide, zirconium oxide, tin oxide or mixtures thereof, said methodcomprising contacting the molecular sieve with acetic acid or a mixtureof acetic acid and pyridine at elevated temperature for a timesufficient to remove tetraethylammonium organic template from themolecular sieve.
 2. The method of claim 1 wherein the molecular sievehas the topology of zeolite beta.
 3. The method of claim 1 wherein theelevated temperature is 60° C. or less.
 4. The method of claim 1 whereinthe elevated temperature is from about 80° C. to about 135° C.
 5. Amethod of removing an organic template from the pores of a molecularsieve and at the same time removing zinc atoms from the framework of themolecular sieve, wherein the molecular sieve comprises an oxide ofsilicon, an oxide of zinc and, optionally, an oxide selected fromaluminum oxide, boron oxide, gallium oxide, vanadium oxide, iron oxide,titanium oxide and mixtures thereof, and having the framework topologyof zeolite beta, said method comprising contacting the molecular sievewith acetic acid or a mixture of acetic acid and pyridine at elevatedtemperature for a time sufficient to remove essentially all of theorganic template and zinc from the molecular sieve.
 6. The method ofclaim 5 wherein the elevated temperature is about 60° C. or less.
 7. Themethod of claim 5 wherein the elevated temperature is from about 80° C.to about 135° C.
 8. The product produced by the method of claim
 5. 9. Amethod of making a crystalline material comprising (1) contacting inadmixture under crystallization conditions a source of silicon oxide, asource of zinc oxide, a source of lithium or a mixture of lithium andanother alkali metal and a templating agent comprising atetraethylammonium cation until a crystalline material comprised ofoxides of silicon and zinc and having the topology of zeolite beta areformed, (2) contacting the crystals with acetic acid or a mixture ofacetic acid and pyridine at an elevated temperature of about 60° C. orless for a time sufficient to remove essentially all of the organictemplate and zinc from the crystals, and (3) contacting the crystalswith a solution containing a source of aluminum, boron, gallium, iron,titanium, vanadium, zirconium, tin or mixtures thereof.
 10. The productproduced by the method of claim 9.